Most organic materials are susceptible, to some degree, to attack by a variety of natural pests, including fungus and insects. Susceptible materials include building materials (such as wood) and industrial materials (such as wet pulps, papers, mats, fibres, leathers, adhesives, paints, synthetic resins and, again, wood) the growth of undesirable fungi on these materials can lead not only to contamination but also to structural damage. In the past, reasonably effective control of fungi on such materials has been achieved by the application to these materials of a variety of anti-fungal compounds. The compounds most commonly employed for this purpose are organic compounds of heavy metals (e.g. compounds of lead or tin, particularly tributyltin oxide) or chlorinated phenols (such as pentachlorophenol). However, these substances are very toxic to humans and other animals and thus not only are they dangerous to handle during application, but they may also give rise to danger during use of the material treated with them. Furthermore, environmental pollution may occur if inadequate safety precautions are taken during treatment of organic materials with these anti-fungal agents or during the use or destruction (e.g. by incineration) of the materials treated. Accordingly, although these anti-fungal agents have proven of great value in the past, it is anticipated that their future use will be restricted or even banned.
However, the world's diminishing resources make it ever more vital that materials should be adequately preserved. For example, wood preservation has become of increasing importance in recent years due to increasing world demands upon dwindling forest resources and because of the introduction of new building processes (e.g. the prefabricatd frame process) and high temperature and humidity conditions in many parts of the world. This demand for preservatives for wood and other organic materials has not been met completely by preservatives of the chlorophenol, organotin or inorganic adhesive types, since they not only (as explained above) may be poisonous, but they may be inadequately effective, have an offensive smell and contaminate the material being treated, which makes it difficult to handle the material easily and safely. There is, therefore, a strong demand for a new anti-fungal and preservative agent which is more effective, easier to handle and safer.
Japanese patent application (examined) No. 19077/66 discloses a compound of general formula IC.tbd.C.CH.sub.2 OR.sup.1 (in which R' represents a phenyl or benzyl group which is unsubstituted or has one or more substituents, the substituents being on the aromatic nucleus and selected from halogen atoms, lower alkyl groups, nitro groups, carbamoyl groups, carboxyl groups and carboalkoxy groups); these compounds have been proposed for use as industrial anti-fungal agents.
Similar iodopropargyl derivatives are disclosed in Japanese patent application (examined) No. 33182/74, (which corresponds to U.S. Pat. No. 3,660,499) these iodopropargyl derivatives being of formula ArOCH.sub.2 OCH.sub.2 C.tbd.CI (in which Ar represents a phenyl group, a naphthyl group or a quinolyl group which are unsubstituted or have an alkyl, halogen or nitro substituent). These compounds have been suggested as fungicides. Similar 1-iodo-alkyne derivatives are disclosed in Japanese patent application (unexamined) No. 31036/75 (which corresponds to U.S. Pat. No. 3,780,089) and suggested for use as fungicides.
3-Benzoyloxy-1-iodo-1-propyne is disclosed in Chemical Abstracts 63 1718 g (1965); however, no potential use or activity is described for this compound. Also, 1-acetoxy-1-iodo-1-propyne is disclosed in Chemical Abstracts 72, 3049 v; however, only its phytological activity, especially chemical pruning activity is disclosed.
After thorough study of a wide variety of compounds, we have now found that 3-benzoyloxy-1-iodo-1-propyne and 3-acetoxy-1-iodo-1-propyne and a closely related group of novel compounds have excellent anti-fungal activity and, moreover, have preservative and anti-insect (particularly termiticidal) activity.